An optical device comprising a polarization diversity coupler is described in “A polarization-diversity wavelength duplexer circuit in silicon-on-insulator photonics wires” (W. Bogaerts et al., Vol. 15, No. 4, Optics Express 1568). This optical device achieves polarization insensitive operation through a polarization diversity approach in which 2-D grating fiber couplers are used as integrated polarization splitters.